Meet fat. It's the subject of this little book, in this frustratingly uneven series of little books about subjects you'd like as not never assumed to find yourself reading about – although you'll have to decide if it's titled for the noun or the adjective, or in which proportion a bit of both. It's not exactly the biological entity you think it is – and human fat, which we concentrate on, comes in at least three shades, white, brown and the beige in the middle. It's seldom met with on the body of an Olympic swimmer, and that's no bad thing, and it is commonly associated with opera singers – but as it actually helps them in their craft that's no bad thing either. Again, I'll leave you to work out which is more essential. And a final thought experiment – would Delacroix's Marianne have an ounce of the impetus if she was one those anorexic-seeming, Cosette-like waifs?

That's not to say I would ever call Marianne fat. In my lecherous boo hiss male gaze, a woman who is fat is someone whose stomach out-projects her breasts. A simple, objective rule – but that's not to say either side is at fault, nor that any one side is "aesthetically compelling", or allowed a rampant sex life, is refused my little place in their circle or a book published. It's not just a matter of over-eating, as the snappy riposte to the calorie counters here proves. We get the full medical consideration of fatness here, in fact, alongside, inevitably given the very left-wing bias of these books, more than enough lambasting of the allegedly sexist, historically racist, and any-ist-imaginable critique of the pyknic. This from an author who thinks all Lane Bryant (thanks for the tip) models are plus-sized.

To consider these pages in the franchise to which they belong, they are still as personal, as insular and as at-times awkward as is the norm. This is less concerned with the social history of fatness – the way we went from applauding the cushiony nude to the, er, more bony, the way our love of the totemic buxom and arsey fertility fetish of prehistory became dumped for the much skinnier as an emblem of the "correct" way to be as a woman. Nowhere here is the controversy when the British restaurant chain Little Chef's mascot lost about four stone overnight and was forced to be even littler, to pretend their motorway service junk was actually healthy.

No, what we do get is an academic – still highly personal, but very academic – look at what it might mean to be, as the porn sites have it, "thick" or "chubby". I'll admit to skipping a few "oh damn that slavery business" pages, and some later "people identified at birth as whichever gender" paragraphs just annoyed the hell out of me, but on the whole this works. I've long since stopped wishing the editors of these books sought the best book about each subject, as opposed to accepting just "the book about this subject I want to write and the heck with you cis bastiches", but on the whole this does veer more towards being the best book the subject would get. A plumped-up four stars.